The Mormon cricket (''Anabrus simplex'') is a large

insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pa ...

that can grow to almost in length. It lives throughout western

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and th ...

rangeland Rangelands are grasslands, shrublands, woodlands, wetlands, and deserts that are grazed by domestic livestock or wild animals. Types of rangelands include tallgrass and shortgrass prairies, desert grasslands and shrublands, woodlands, sava ...

s dominated by

sagebrush Sagebrush is the common name of several woody and herbaceous species of plants in the genus '' Artemisia''. The best known sagebrush is the shrub '' Artemisia tridentata''. Sagebrushes are native to the North American west. Following is an al ...

and

forb A forb or phorb is an herbaceous flowering plant that is not a graminoid (grass, sedge, or rush). The term is used in biology and in vegetation ecology, especially in relation to grasslands and understory. Typically these are dicots without woo ...

s. Despite its name, the Mormon cricket is actually a

shield-backed katydid The Tettigoniinae are a subfamily of bush crickets or katydids, which contains hundreds of species in about twelve tribes. Distribution The greatest diversity is in the Palaearctic region and many of the familiar European species of bush cricke ...

. It takes its name from Mormon settlers in Utah, who encountered them while pushing westward, and for the prominent role they play in the miracle of the gulls. Although flightless, the Mormon cricket is capable of traveling up to two kilometers a day in its swarming phase, during which it is a serious agricultural pest and traffic hazard.

Description

Mormon crickets have variable coloration. The overall color may be black, brown, red, purple or green. The "shield" (pronotum or modified

prothorax The prothorax is the foremost of the three segments in the thorax of an insect, and bears the first pair of legs. Its principal sclerites (exoskeletal plates) are the pronotum ( dorsal), the prosternum ( ventral), and the propleuron ( lateral) o ...

that covers

vestigial Vestigiality is the retention, during the process of evolution, of genetically determined structures or attributes that have lost some or all of the ancestral function in a given species. Assessment of the vestigiality must generally rely on co ...

wings) behind the head may have colored markings. The abdomen may appear to be striped. Females have a long

ovipositor The ovipositor is a tube-like organ used by some animals, especially insects, for the laying of eggs. In insects, an ovipositor consists of a maximum of three pairs of appendages. The details and morphology of the ovipositor vary, but typical ...

, which should not be mistaken for a

stinger A stinger (or sting) is a sharp organ found in various animals (typically insects and other arthropods) capable of injecting venom, usually by piercing the epidermis of another animal. An insect sting is complicated by its introduction of ve ...

. Both sexes have long antennae. Mormon crickets may undergo morphological changes triggered by high population densities, similar to those seen in

locust Locusts (derived from the Vulgar Latin ''locusta'', meaning grasshopper) are various species of short-horned grasshoppers in the family Acrididae that have a swarming phase. These insects are usually solitary, but under certain circumstanc ...

s. The most noticeable change is in coloration: solitary individuals typically have green or purple coloration, while swarming individuals are often black, brown or red.

Life cycle

Mormon cricket eggs hatch mostly in the spring after they are laid, although in some areas eggs may take as many as five years to hatch. Hatching begins when soil temperatures reach . The

nymphs A nymph ( grc, νύμφη, nýmphē, el, script=Latn, nímfi, label=Modern Greek; , ) in ancient Greek folklore is a minor female nature deity. Different from Greek goddesses, nymphs are generally regarded as personifications of nature, are ...

pass through seven

instar An instar (, from the Latin '' īnstar'', "form", "likeness") is a developmental stage of arthropods, such as insects, between each moult (''ecdysis''), until sexual maturity is reached. Arthropods must shed the exoskeleton in order to grow or ...

s before reaching the adult stage, typically taking 60 to 90 days. Breeding begins within 10 to 14 days of reaching the adult stage. The male passes to the female a large

spermatophore A spermatophore or sperm ampulla is a capsule or mass containing spermatozoa created by males of various animal species, especially salamanders and arthropods, and transferred in entirety to the female's ovipore during reproduction. Spermatophore ...

which can be up to 27% of his body weight. The spermatophore is mostly food for the female to consume but also contains sperm to fertilize her eggs. This

nuptial gift A nuptial gift is a nutritional gift given by one partner in some animals' sexual reproduction practices. Formally, a nuptial gift is a material presentation to a recipient by a donor during or in relation to sexual intercourse that is not simpl ...

causes swarming-phase females to compete for males, a behavior not seen in solitary-phase females. The female lays her eggs by thrusting her ovipositor deep into the soil. Each female can lay over one hundred eggs, with individual eggs having the appearance of a grain of rice with a gray to purplish color.

Swarming

The Mormon cricket exists in populations of relatively low density throughout most of its range. At certain times and places, however, population explosions or infestations occur in which large numbers of the crickets form roving bands. These bands may include millions of individuals and be found with densities of up to 100 individuals per square meter. These infestations may last years or even decades, and are characterized by a gradual increase and then decrease in population. The factors that trigger these infestations are poorly understood, but are thought to be weather-related. Research published in 2006 shows that Mormon crickets move in these migratory bands, firstly to find new sources of the critical nutrients of protein and salt, and secondly to avoid being eaten by hungry crickets approaching from the rear. The Mormon cricket's cannibalistic behavior may lead to

swarm behavior Swarm behaviour, or swarming, is a collective behaviour exhibited by entities, particularly animals, of similar size which aggregate together, perhaps milling about the same spot or perhaps moving ''en masse'' or migrating in some direction. ...

because crickets may need to move constantly forward to avoid attacks from behind. When a large band crosses a road, it can create a safety hazard by causing distracted revulsion on the part of the driver, and by causing the road surface to become slick with crushed crickets. The crickets also can cause devastation to agriculture.

Diet

The Mormon cricket shows a marked preference for

s, but

grasses Poaceae () or Gramineae () is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos and the grasses of natural grassland and species cultivated in lawns ...

and

shrub A shrub (often also called a bush) is a small-to-medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from tree ...

s such as

are also consumed. Mormon crickets also eat insects, including other Mormon crickets (especially individuals that have been killed or injured by automobiles or insecticides). Cannibalistic behavior may be a result of protein and salt deficiency; swarming behavior may in turn be a strategy to avoid predation by other Mormon crickets. A journal documenting an 1846 journey along the Oregon Trail describes an encounter with the crickets and notes their cannibalistic behavior:

The ground, for a strip of about four miles, was covered with black crickets of a large size. I saw some that were about three inches in length, and measuring about three-fourths of an inch in diameter; but the common size were two inches in length and one-half or five-eighths of an inch in diameter; their legs were large in proportion to the size of their bodies. Some were singing on stalks of wild sage; others crawling in every direction. Our teams made great havoc among them; so numerous were they that we crushed them at every step. As soon as one was killed, others of them would alight upon it and devour it.Palmer, Joel, ''Journal of Travels over the Rocky Mountains, to the Mouth of the Columbia River'', p.79 (1847)
/ref>

Control

Mormon crickets are preyed upon by a wide variety of birds and mammals. These predators include California gulls,

crows The Common Remotely Operated Weapon Station (CROWS) is a series of remote weapon stations used by the US military on its armored vehicles and ships. It allows weapon operators to engage targets without leaving the protection of their vehicle. ...

coyote The coyote (''Canis latrans'') is a species of canine native to North America. It is smaller than its close relative, the wolf, and slightly smaller than the closely related eastern wolf and red wolf. It fills much of the same ecological nich ...

s and various rodents. There are no predators that specialize on Mormon crickets, which may be explained by the cricket's migratory habits and large population fluctuations. ''Gordius robustus'', a species of

horsehair worm Nematomorpha (sometimes called Gordiacea, and commonly known as horsehair worms, hairsnakes, or Gordian worms) are a phylum of parasitoid animals superficially similar to nematode worms in morphology, hence the name. Most species range in size fr ...

, is a parasite of the Mormon cricket, as is ''Ooencyrtus anabrivorus''. The most common chemical control method used is

carbaryl Carbaryl (1-naphthyl methylcarbamate) is a chemical in the carbamate family used chiefly as an insecticide. It is a white crystalline solid previously sold under the brand name Sevin, which was a trademark of the Bayer Company. The Sevin trademark ...

(typically sold as "Sevin Dust") bait. This bait kills both the Mormon crickets that eat the bait, and the crickets that eat crickets that have eaten the bait. Insecticides applied directly to crops may kill the insects, but due to the large size of swarms, this method usually does not save the crop from being destroyed. As Mormon crickets are flightless, physical barriers may be effective. Barriers should be at least two feet high and made of a smooth material. Residents of some small towns have used boom boxes and sound systems playing

hard rock Hard rock or heavy rock is a loosely defined subgenre of rock music typified by aggressive vocals and distorted electric guitars. Hard rock began in the mid-1960s with the garage, psychedelic and blues rock movements. Some of the earliest ha ...

music in attempts to divert the moving swarms away from crops and houses. Another method for the control of Mormon crickets is the use of a biopesticide based on the fungus '' Nosema locustae''. ''N. locustae'' is a naturally occurring microbe the spores of which kill orthopterans by interfering with the digestive system. According to the

U.S. Environmental Protection Agency The Environmental Protection Agency (EPA) is an Independent agencies of the United States government, independent executive agency of the United States federal government tasked with environmental protection matters. President Richard Nixon pro ...

, its use has no adverse effect on humans or the environment.

Historical

Mormon crickets appear in some traditional Native American diets. In 2003, officials in Utah, Idaho and Nevada said that year's infestation might be the worst in recent history.

References

External links

Mormon cricket (''Anabrus simplex'')
University of Florida description page with images and male cricket song

''New York Times'' article {{Taxonbar, from=Q2789177 Insects of the United States Tettigoniinae Insects described in 1852 Taxa named by Samuel Stehman Haldeman